11 resultados para Ranking of importance of the nodes
em CORA - Cork Open Research Archive - University College Cork - Ireland
Design and implementation of the embedded capacitance layers for decoupling of wireless sensor nodes
Resumo:
In this paper, the embedded capacitance material (ECM) is fabricated between the power and ground layers of the wireless sensor nodes, forming an integrated capacitance to replace the large amount of decoupling capacitors on the board. The ECM material, whose dielectric constant is 16, has the same size of the wireless sensor nodes of 3cm*3cm, with a thickness of only 14μm. Though the capacitance of a single ECM layer being only around 8nF, there are two reasons the ECM layers can still replace the high frequency decoupling capacitors (100nF in our case) on the board. The first reason is: the parasitic inductance of the ECM layer is much lower than the surface mount capacitors'. A smaller capacitance value of the ECM layer could achieve the same resonant frequency of the surface mount decoupling capacitors. Simulation and measurement fit this assumption well. The second reason is: more than one layer of ECM material are utilized during the design step to get a parallel connection of the several ECM capacitance layers, finally leading to a larger value of the capacitance and smaller value of parasitic. Characterization of the ECM is carried out by the LCR meter. To evaluate the behaviors of the ECM layer, time and frequency domain measurements are performed on the power-bus decoupling of the wireless sensor nodes. Comparison with the measurements of bare PCB board and decoupling capacitors solution are provided to show the improvement of the ECM layer. Measurements show that the implementation of the ECM layer can not only save the space of the surface mount decoupling capacitors, but also provide better power-bus decoupling to the nodes.
Resumo:
In this PhD study, mathematical modelling and optimisation of granola production has been carried out. Granola is an aggregated food product used in breakfast cereals and cereal bars. It is a baked crispy food product typically incorporating oats, other cereals and nuts bound together with a binder, such as honey, water and oil, to form a structured unit aggregate. In this work, the design and operation of two parallel processes to produce aggregate granola products were incorporated: i) a high shear mixing granulation stage (in a designated granulator) followed by drying/toasting in an oven. ii) a continuous fluidised bed followed by drying/toasting in an oven. In addition, the particle breakage of granola during pneumatic conveying produced by both a high shear granulator (HSG) and fluidised bed granulator (FBG) process were examined. Products were pneumatically conveyed in a purpose built conveying rig designed to mimic product conveying and packaging. Three different conveying rig configurations were employed; a straight pipe, a rig consisting two 45° bends and one with 90° bend. It was observed that the least amount of breakage occurred in the straight pipe while the most breakage occurred at 90° bend pipe. Moreover, lower levels of breakage were observed in two 45° bend pipe than the 90° bend vi pipe configuration. In general, increasing the impact angle increases the degree of breakage. Additionally for the granules produced in the HSG, those produced at 300 rpm have the lowest breakage rates while the granules produced at 150 rpm have the highest breakage rates. This effect clearly the importance of shear history (during granule production) on breakage rates during subsequent processing. In terms of the FBG there was no single operating parameter that was deemed to have a significant effect on breakage during subsequent conveying. A population balance model was developed to analyse the particle breakage occurring during pneumatic conveying. The population balance equations that govern this breakage process are solved using discretization. The Markov chain method was used for the solution of PBEs for this process. This study found that increasing the air velocity (by increasing the air pressure to the rig), results in increased breakage among granola aggregates. Furthermore, the analysis carried out in this work provides that a greater degree of breakage of granola aggregates occur in line with an increase in bend angle.
Resumo:
The wave energy industry is progressing towards an advanced stage of development, with consideration being given to the selection of suitable sites for the first commercial installations. An informed, and accurate, characterisation of the wave energy resource is an essential aspect of this process. Ireland is exposed to an energetic wave climate, however many features of this resource are not well understood. This thesis assesses and characterises the wave energy resource that has been measured and modelled at the Atlantic Marine Energy Test Site, a facility for conducting sea trials of floating wave energy converters that is being developed near Belmullet, on the west coast of Ireland. This characterisation process is undertaken through the analysis of metocean datasets that have previously been unavailable for exposed Irish sites. A number of commonly made assumptions in the calculation of wave power are contested, and the uncertainties resulting from their application are demonstrated. The relationship between commonly used wave period parameters is studied, and its importance in the calculation of wave power quantified, while it is also shown that a disconnect exists between the sea states which occur most frequently at the site and those that contribute most to the incident wave energy. Additionally, observations of the extreme wave conditions that have occurred at the site and estimates of future storms that devices will need to withstand are presented. The implications of these results for the design and operation of wave energy converters are discussed. The foremost contribution of this thesis is the development of an enhanced understanding of the fundamental nature of the wave energy resource at the Atlantic Marine Energy Test Site. The results presented here also have a wider relevance, and can be considered typical of other, similarly exposed, locations on Ireland’s west coast.
Resumo:
Actinins are cytoskeleton proteins that cross-link actin filaments. Evolution of the actinin family resulted in the formation of Ca++-insensitive muscle isoforms (actinin-2 and- 3) and Ca++-sensitive non-muscle isoforms (actinin-1 and -4) with regard to their actin-binding function. Despite high sequence similarity, unique properties have been ascribed to actinin-4 compared with actinin-1. Actinin-4 is the predominant isoform reported to be associated with the cancer phenotype. Actinin-4, but not actinin-1, is essential for normal glomerular function in the kidney and and is able to translocate to the nucleus to regulate transcription. To understand the molecular basis for such isoform-specific functions I have comprehensively compared these proteins in terms of localisation, migration, alternative splicing, actin-binding properties, heterodimer formation and molecular interactions for the first time. This work characterises a number of commercially available actinin antibodies and in doing so, identifies actinin-1, -2 and -4 isoform-specific antibodies that enabled studies of actinin expression and localisation. This work identifies the actinin rod domain as the predominant domain that influences actinin localisation however localisation is likely to be effected by the entire actinin protein. si-RNA- mediated knockdown of actinin-1 and -4 did not affect migration in a number of cell lines highlighting that migration may only require a fraction of total non-muscle actinin levels. This work finds that the Ca++-insensitive variant of actinin-4 is expressed only in the nervous system and thus cannot be regarded as a smooth muscle isoform, as is the case for the Ca++-insensitive variant of actinin-1. This work also identifies a previously unreported exon 19a+19b expressing variant of actinin-4 in human skeletal muscle. This work finds that alternative splice variants of actinin-1 and -4 are co-expressed in a number of tissues, in particular the brain. In contrast to healthy brain, glioblastoma cells express Ca++-sensitive variants of both actinin-1 and -4. Actin-binding properties of actinin-1 and -4 are similar and are unlikely to explain isoform-specific functions. Surprisingly, this work reveals that actinin-1/-4 heterodimers, rather than homodimers, are the most abundant form of actinin in many cancer cell lines. Taken together this data suggests that actinin-1 and -4 cannot be viewed as distinct entities from each other but rather as proteins that can exist in both homodimeric and heterodimeric forms. Finally, this work employs yeast two-hybrid and proteomic approaches to identify actinin-interacting proteins. In doing so, this work identifies a number of putative actinin-4 specific interacting partners that may help to explain some of the unique functions attributed the actinin-4. The observation of alternative splice variants of actinin-1 and -4 combined with the observed potential of these proteins to form homodimers and heterodimers suggests that homodimers and heterodimers with novel actin-binding properties and interaction networks may exist. The ability to behave in this manner may have functional implications. This may be of importance considering that these proteins are central to such processes as cell migration and adhesion. This significantly alters our view of the non-muscle actinins.
Resumo:
Growth/differentiation factor 5 (GDF5) and glial cell line-derived neurotrophic factor (GDNF) are neurotrophic factors that promote the survival of midbrain dopaminergic neurons in vitro and in vivo. Both factors have potent neurotrophic and neuroprotective effects in rat models of Parkinson's disease (PD), and may represent promising new therapies for PD. The aim of the present study was to investigate the endogenous expression and function of GDF5 and GDNF in the nigrostriatal dopaminergic system during development and in rat models of PD. Examination of the temporal expression patterns of endogenous GDF5, GDNF, and their respective receptors, in the developing and adult nigrostriatal dopaminergic system suggest that these factors play important roles in promoting the survival and maturation of midbrain dopaminergic neurons during the period of postnatal programmed cell death. The relative levels of GDF5 and GDNF mRNAs in the midbrain and striatum, and their individual temporal expression patterns during development, suggest that their modes of actions are quite distinct in vivo. Furthermore, the sustained expression of GDF5, GDNF, and their receptors into adulthood suggest roles for these factors in the continued support and maintenance of mature nigrostriatal dopaminergic neurons. The present study found that endogenous GDF5, GDNF, and their receptors are differentially expressed in two 6-hydroxydopamine-induced lesion adult rat models of PD. In both terminal and axonal lesion models of PD, GDF5 mRNA levels in the striatum increased at 10 days post-lesion, while GDNF mRNA levels in the nigrostriatal system decreased at 10 and 28 days post-lesion. Thus, despite the fact that exogenous GDF5 and GDNF have similar effects on midbrain dopaminergic neurons in vitro and in vivo, their endogenous responses to a neurotoxic injury are quite distinct. These results highlight the importance of studying the temporal dynamic changes in neurotrophic factor expression during development and in animal models of PD.
Resumo:
Introduction: Worldwide, governments are striving to keep people in work to an older age. However, little is known about the effects of work on an older workforce. This thesis aims to investigate the importance of job characteristics to the antecedents and evolution of cardiovascular disease and functional limitations for the older worker (50+ years). Methods: Three studies were used in this thesis. The 5C (Cork Coronary Care Case- Control) Study investigated the association between job strain and a coronary event in males (n=208) 35-74 years old. The Mitchelstown Study examined the association between job characteristics and positive lifestyle behaviours and further, job characteristics and blood pressure for males and females 50-69 years (n=2,047). Finally, the Cork & Kerry Study investigated the physical effects of manual work and reported functional limitations/disabilities in a sample of 60-80 year olds (n=362). Results: Results from the 5C Study show a clear difference between younger (<50 years) and older (≥50 years) workers, with older workers who had a coronary event more likely to have high job strain and low job control. Data from the Mitchelstown Study showed workers with intermediate possibility for development or high quantitative demands (versus low) at work significantly more likely to have co-occurrence of positive lifestyle behaviours. Further, those who had high possibility for development were more likely to have high systolic blood pressure with no indication of recovery from this activation at night. Physically demanding work as reported by the participants of the Cork & Kerry Study was associated with functional limitations and activities of daily living disability for both the paid and unpaid worker. Discussion: The findings from this piece of work highlight the necessity to examine job characteristics and health outcomes in isolation for the over fifties. The challenge is to get this information into the workplace.
Resumo:
The human gastrointestinal (GI) tract is colonized by a dense and diverse bacterial community, the commensal microbiota, which plays an important role in the overall health of individuals. This microbiota is relatively stable throughout adult life, but may fluctuate over time with aging and disease. The adaptation of the gut microbiota to our changing life-style is probably the reason for the large inter-individual variation observed among different people. Since the gut microbiota plays an essential role in interactions with host metabolism, it is of utmost importance to explore this relationship. The elderly intestinal microbiota has been the subject of a number of studies in recent years. The results presented in this thesis have further contributed to the expansion of knowledge related to gut microbiota research highlighting the combined effect of culture based and molecular methods as powerful tools for understanding the true impact of microbes. The degree of correlation between measurements from both methods suggested that a single method is capable of profiling intestinal Bifidobacterium spp., Lactobacillus spp. and Enterobacteriaceae populations. Bacteriocins have shown great promise as alternatives to traditional antibiotics. In this respect, the isolation and characterisation of bacteriocinogenic strains are important due to growing evidence indicating bacteriocin production as a potential probiotic trait by virtue of strain dominance and/or pathogen inhibition in the mammalian intestine. The selection pressure applied on the bacterial population during antibiotic usage is the driving force for the emergence of antibiotic resistant bacteria. Identification of antibiotic resistant isolates opens up the possibility of using such probiotics to offset the problems caused by antibiotics to the gut microbiota and to improve the intestinal microbial environment. Future work is required to explore the culture collection housing thousands of bacterial isolates as a valuable source of potential probiotics for use for the elderly Irish community.
Resumo:
The present study investigated the genotoxic potential of the marine biotoxins okadaic acid (OA) and azaspiracids (AZAs). Harmful algae blooms (HABs) are an increasing global problem with implications for the ecosystem, economy and human health. Most data available on human intoxication are based on acute toxicity. To date, limited data has been published on possible long term effects, carcinogenicity and genotoxicity. To investigate genotoxicity in the present study, DNA fragmentation was detected using the COMET assay. In contrast to most other available studies, two further endpoints were included. The Trypan Blue Exclusion assay was used to provide information on possible cytotoxicity and assess the right concentration range. Flow cytometer analysis was included to detect the possible involvement of apoptotic processes. In house background data for all endpoints were established using positive controls. Three different cell lines, Jurkat T cells, CaCo-2 cells and HepG-2 cells, representing the main target organs, were exposed to OA and AZA1-3 at different concentrations and exposure times. Data obtained from the COMET assay showed an increase in DNA fragmentation for all phycotoxins, indicating a modest genotoxic effect. However, the data obtained from the Trypan Blue Exclusion assay showed a clear reduction in cell viability and cell number, indicating the involvement of cytotoxic and/or apoptotic processes. This is supported by data obtained by flow cytometer analysis. All phycotoxins investigated showed signs of early/late apoptosis. Therefore, the combined observations made in the present study indicate that OA and AZA1-3 are not genotoxic per se. Apoptotic processes appear to make a major contribution to the observed DNA fragmentation. The information obtained in this study stresses the importance of inclusion of additional endpoints and appropriate positive controls in genotoxicity studies. Furthermore, these data can assist in future considerations on risk assessment, especially regarding repeated exposure and exposure at sub-clinical doses.
Resumo:
The central research question of this thesis asks the extent to which Irish law, policy and practice allow for the application of the United Nations Convention on the Rights of the Child (CRC) to pre-natal children. First, it is demonstrated that pre-natal children can fall within the definition of ‘child’ under the Convention and so the possibility of applying the Convention to children before birth is opened. Many State Parties to the CRC have interpreted it as applicable to pre-natal children, while others have expressed that it only applies from birth. Ireland has not clarified whether or not it interprets it as being applicable from conception, birth, or some other point. The remainder of the thesis examines the extent to which Ireland interprets the CRC as applicable to the pre-natal child. First, the question of whether Ireland affords to the pre-natal child the right to life under Article 6(1) of the Convention is analysed. Given the importance of the indivisibility of rights under the Convention, the extent to which Ireland applies other CRC rights to pre-natal children is examined. The rights analysed are the right to protection from harm, the right to the provision of health care and the procedural right to representation. It is concluded that Ireland’s laws, policies and practices require urgent clarification on the issue of the extent to which rights such as protection, health care and representation apply to children before birth. In general, there are mixed and ad hoc approaches to these issues in Ireland and there exists a great deal of confusion amongst those working on the frontline with such children, such as health care professionals and social workers. The thesis calls for significant reform in this area in terms of law and policy, which will inform practice.
Resumo:
This thesis analyses the influence of the esoteric tradition on D.H. Lawrence and W.B. Yeats’ thought and examines both authors’ writings in light of the antidemocratic political religions that emerged during and after their respective careers. While a number of extant studies investigate the connection between modernism and the occult and a number of critics have discussed the importance of antidemocratic politics to modernism, this study is unique in its emphasis on the relationship between modernist esotericism and antidemocratic politics, and in its insistence that the interconnection between the two constitutes a fundamental part of both authors’ world-views. This study calls for the development of a multivalent understanding of modernism, which appears as neither a “cultural movement identifiable with bourgeois, capitalist, paternalist, ethnocentrist, phallocentrist, and logocentrist ideologies” (Surette 5) nor entirely the opposite; Romantic, feministic, primitivistic and countercultural. Rather, modernism will be shown to have encompassed both of these ideological orientations, effectively operating on a double front in its crusade to establish a new age. This complexity is visible in both Lawrence and Yeats’ work, as both authors advocate a return to traditional structures while simultaneously endeavouring to usher Western civilisation into a new modern paradigm. Although they primarily grounded their writings in a mythico-pastoral discourse that masked the practical implications of their revolutionary agendas, both authors possessed an attraction to Futurist thought and, albeit rarely, showed an awareness that the change they envisioned could not be brought about without a radical intervention in the political and economic sectors – an intervention that would necessarily take place through the medium of the “machine” from which they were often so adamant to distance themselves. This fusion of technophilic and Arcadian thought-currents – dubbed “archeofuturism” by the French right-wing intellectual Guillaume Faye – constitutes the central focus of this discussion of Lawrentian and Yeatsian thought.
Resumo:
Sinapic acid (SA) is a nutraceutical with known anti-oxidant, anti-microbial, anti-inflammatory, anti-cancer, and anti-anxiety properties. Novel co-crystals of SA were prepared with co-formers belonging to the category of GRAS [isonicotinic acid (INC), nicotinamide (NIA)], non-GRAS [4-pyridinecarbonitrile (PYC)], and active pharmaceutical ingredients (APIs) [6-propyl-2-thiouracil (PTU)] list of compounds. Structural study based on the X-ray crystal structures revealed the intermolecular hydrogen-bonded interactions and molecular packing. The crystal structure of sinapic acid shows the anticipated acid-acid homodimer along with discrete hydrogen bonds between the acid carbonyl and the phenolic moiety. The robust acid-acid homodimer appears to be very stable and is retained in the structures of two co-crystals (SA[middle dot]NIA and SA[middle dot]PYC). In these cases, co-crystallization occurs via intermolecular phenol O-H[three dots, centered]Naromatic hydrogen bonds between the co-formers. In the SA[middle dot]PTU[middle dot]2MeCN co-crystal the acid-acid homodimer gives way to the anticipated acid-amide heterodimer, with the phenolic moiety of SA hydrogen-bonded to acetonitrile. Attempts at obtaining the desolvated co-crystal led to lattice breakdown, thus highlighting the importance of acetonitrile in the formation of the co-crystal. Among the co-crystals examined, SA[middle dot]INC (5 weeks), SA[middle dot]NIA (8 weeks) and SA[middle dot]PYC (5 weeks) were found to be stable under accelerated humidity conditions (40 [degree]C, 75% RH), whereas SA[middle dot]PTU[middle dot]2MeCN decomposed after one week into individual components due to solvent loss.